The present invention is directed to an isotope seeding system that controls the release of radioactive seeds for treatment of cancerous cells during cancer treatment procedures, such as prostate surgery.
The implantation of radioactive seeds, such as iodine, for the treatment of cancer, particularly prostate cancer, is well-known in the art. Traditionally, isotope seeding systems (as shown in FIG. 1) have comprised an obturator, a hub assembly, and a cannula. The customary open seeding technique was used to dispense seeds around cancerous cells. However, individual seeds often move slightly after leaving the rigid confines of a needle, and accordingly, precise alignment of seeds has often been difficult to achieve.
To reduce the migration of seeds, ultrasound-guided radioactive seed implantation, using devices such as the I-125 Rapid Strand.TM. supplied by Medi-Physics, Inc., has been developed. In such prior art devices, radioactive seeds have been embedded in a somewhat stiffened, dissolvable vinyl carrier. The specified number of seeds are then implanted in a linear fashion during needle withdrawal. As a result, seed migration has been minimized. However, prior art devices, such as the one shown in FIG. 1, have not always resulted in the optimal linear arrangement of radioactive seeds around cancerous cells, since some seeds become misaligned and/or released from the vinyl carrier while still in the hub. Moreover, such prior art configurations may result in jamming of the radioactive seeds and/or the dissolvable web nettings within the hub during cancer treatment procedures. Jamming of the radioactive seeds can occur in the hub regardless of whether the radioactive seeds are freely located within the hub or preliminarily positioned within the dissolvable web nettings.
In FIG. 1, which illustrates a prior art system, "a" represents the initial inner diameter of the hub assembly, which, for example, can be 0.168 inches, and "b" represents the operable length of the hub assembly, which, for example, can be 0.745 inches. Moreover, "c" is the length of the first conical section, which can typically be 0.3 inches, while "d" is the slope from the proximal end to the distal end of the first conical section, which is approximately 1.degree.43'06". Further, "e", the slope from the proximal to the distal end of the second conical section, is approximately 7.degree.. However, these prior art dimensions, and subsequent configuration, can result in the premature release of radioactive seeds from within the wrapped vinyl carrier in the hub assembly; prior to transmission through the cannula and release into the organism's tissue that surrounds cancerous cells. Additionally, regardless of whether the radioactive seeds are first enveloped in the wrapped vinyl netting, such prior art dimensions may cause radioactive seeds to become jammed within the hub assembly during cancer treatment procedures.
It is therefore an object of the present invention to reduce radiation exposure during cancer treatment procedures by more efficiently dispensing radioactive seeds into an organism's tissue;
It is also an object of the present invention to prevent the premature release of radioactive seeds from the dissolvable web netting in the hub assembly during cancer treatment procedures and to prevent the jamming of such seeds in the hub assembly regardless of whether they are freely located or wrapped in dissolvable web netting;
It is a further object of the present invention to maximize the amount of appropriately wrapped or unwrapped radioactive seeds for release around cancerous cells during cancer treatment procedures;
It is yet another object of the present invention to minimize the amount of healthy, non-cancerous tissue that is damaged by either radioactive seeds that have migrated free of wrapped netting during cancer treatment procedures or from jammed radioactive seeds that have been deformed;
It is a further object of the present invention to prevent jamming of the radioactive seeds and/or the dissolvable web netting within the hub assembly during cancer treatment procedures.
These and other objects of the invention will become apparent in light of the present specification, claims and drawings.